+100HP from L98
#1
Member
Thread Starter
+100HP from L98
Hi everybody,
I have 1988 Trans Am GTA with L98 TPI engine, all bone stock only without catalysator, and completely 3" exhaust.
I looked so much this forum about increasing the engine power, but can't connect everything in my head , and make a good setup for around 300hp.
Can anyone tell me exactly which components to buy, in order to get around 100hp on L98?
I know the question sounds stupid, but I read the forum so much that in the end I have no idea how and which parts to compose Headers, runners, rockers, cams, injectors... but what exactly to buy, that's the question
Thank You very much in advance.
Best regards!
I have 1988 Trans Am GTA with L98 TPI engine, all bone stock only without catalysator, and completely 3" exhaust.
I looked so much this forum about increasing the engine power, but can't connect everything in my head , and make a good setup for around 300hp.
Can anyone tell me exactly which components to buy, in order to get around 100hp on L98?
I know the question sounds stupid, but I read the forum so much that in the end I have no idea how and which parts to compose Headers, runners, rockers, cams, injectors... but what exactly to buy, that's the question
Thank You very much in advance.
Best regards!
#3
Supreme Member
iTrader: (8)
Join Date: Jul 2001
Location: New Boston, IL, USA
Posts: 3,204
Likes: 0
Received 6 Likes
on
6 Posts
Car: '90 Formula 350
Engine: 383 SBC
Transmission: ProBuilt S/S 700-R4 & ACT 9" Stall
Axle/Gears: 10 bolt 3.23
Re: +100HP from L98
Do some searches many people include there build specs with there dyno results.
It depends on your budget and the plans for the car. There really isn't any secret formula for power on these cars. It just comes down to how much you want to pay to go fast. If you're just wanting more hp for the strip only many members have used 150 shot on stock good condition 350s with colder plugs and pulling some timing out.
For 300 hp or around there I would just stick with short tube headers. Long tubes are nice but they're a headache.
If you did headers, AFR heads (195 cc), port the intake, roller rockers, and use a ECM compatiable camshaft you should be able to meet your goal easily. Course if you're putting that much money into a stock short block you need to think how many miles are on it also? Are you dumping $2000 of parts into a 350 that has 200k miles or something?
You can have a 500+ HP car but it's probably not going to hook without the normal suspension upgrades (sub frame connectors and etc).
It depends on your budget and the plans for the car. There really isn't any secret formula for power on these cars. It just comes down to how much you want to pay to go fast. If you're just wanting more hp for the strip only many members have used 150 shot on stock good condition 350s with colder plugs and pulling some timing out.
For 300 hp or around there I would just stick with short tube headers. Long tubes are nice but they're a headache.
If you did headers, AFR heads (195 cc), port the intake, roller rockers, and use a ECM compatiable camshaft you should be able to meet your goal easily. Course if you're putting that much money into a stock short block you need to think how many miles are on it also? Are you dumping $2000 of parts into a 350 that has 200k miles or something?
You can have a 500+ HP car but it's probably not going to hook without the normal suspension upgrades (sub frame connectors and etc).
#4
Supreme Member
iTrader: (20)
Re: +100HP from L98
Your looking at something like 220-230whp stock on a good running L98 to 320-330whp on a modded L98.
You will have to upgrade intake to all aftermarket high flow TPI or better like short runner intakes like superram, stealth ram, proflow, miniram, etc.
heads will have to be ported out stockers, mildly ported out aluminum L98's, or aftermarket which is more money but makes power easier to come by. 180-195cc will do. AFR/DART/BRODIX/TRICKFLOW/PROFILER, etc...all great heads and most are really overkill for 330whp but i'd rather have overkill heads and mild cam than too little head and big cam to make up the difference.
I've seen here that a mildly cleaned up L98 headed motor with hotcam sized cam (218 deg intake duration, .500-.525 lift or so) with a ported aftermarket TPI or short runner intake can do 320whp.
All depends on the dyno and tune tho. Some put out higher numbers than others
You will have to upgrade intake to all aftermarket high flow TPI or better like short runner intakes like superram, stealth ram, proflow, miniram, etc.
heads will have to be ported out stockers, mildly ported out aluminum L98's, or aftermarket which is more money but makes power easier to come by. 180-195cc will do. AFR/DART/BRODIX/TRICKFLOW/PROFILER, etc...all great heads and most are really overkill for 330whp but i'd rather have overkill heads and mild cam than too little head and big cam to make up the difference.
I've seen here that a mildly cleaned up L98 headed motor with hotcam sized cam (218 deg intake duration, .500-.525 lift or so) with a ported aftermarket TPI or short runner intake can do 320whp.
All depends on the dyno and tune tho. Some put out higher numbers than others
#5
Junior Member
iTrader: (1)
Join Date: Oct 2008
Location: Los Angeles, CA
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro IROC-Z28
Engine: Stock L98
Transmission: 700R-4
Axle/Gears: 3.23
Re: +100HP from L98
Your looking at something like 220-230whp stock on a good running L98 to 320-330whp on a modded L98.
You will have to upgrade intake to all aftermarket high flow TPI or better like short runner intakes like superram, stealth ram, proflow, miniram, etc.
heads will have to be ported out stockers, mildly ported out aluminum L98's, or aftermarket which is more money but makes power easier to come by. 180-195cc will do. AFR/DART/BRODIX/TRICKFLOW/PROFILER, etc...all great heads and most are really overkill for 330whp but i'd rather have overkill heads and mild cam than too little head and big cam to make up the difference.
I've seen here that a mildly cleaned up L98 headed motor with hotcam sized cam (218 deg intake duration, .500-.525 lift or so) with a ported aftermarket TPI or short runner intake can do 320whp.
All depends on the dyno and tune tho. Some put out higher numbers than others
You will have to upgrade intake to all aftermarket high flow TPI or better like short runner intakes like superram, stealth ram, proflow, miniram, etc.
heads will have to be ported out stockers, mildly ported out aluminum L98's, or aftermarket which is more money but makes power easier to come by. 180-195cc will do. AFR/DART/BRODIX/TRICKFLOW/PROFILER, etc...all great heads and most are really overkill for 330whp but i'd rather have overkill heads and mild cam than too little head and big cam to make up the difference.
I've seen here that a mildly cleaned up L98 headed motor with hotcam sized cam (218 deg intake duration, .500-.525 lift or so) with a ported aftermarket TPI or short runner intake can do 320whp.
All depends on the dyno and tune tho. Some put out higher numbers than others
#6
Member
Join Date: Oct 2007
Location: O'Fallon Mo.
Posts: 413
Likes: 0
Received 1 Like
on
1 Post
Car: 1992 Camaro
Engine: HSR 355, afr 195s, xfi280, Holley e
Transmission: t-5
Axle/Gears: Braced 10 bolt Auburn and 3.73s
Re: +100HP from L98
start with INTAKE, i swapped a stealth ram in my l98 with headers and some bolt on's. crappy tune but its up there. i need some gears bad and a tune but with stealth ram alone it makes one hell of a difference.
#7
Member
Thread Starter
Re: +100HP from L98
Thanks guys,
my car/engine has 52000 miles and I think that it's ready to build up
I don't like nitro, this is street car so I want that power all the time. I don't defined budget for this, but there is no need to buy everything at once.
I spent about 6000$ in last two years to repair the car, because it was in very bad shape, and this is only GTA 5.7 in my country (Serbia). Money is not the problem, but I want to see here is it better to build up L98, or just to buy LS1 with tranny and get 350HP immediately
If I need to spend 3000-4000$ to build up L98, I'd rather buy LS1.
What could I espect from these parts:
First: http://www.firstfuelinjection.com/PDRM1966.JPG
Headers: http://www.summitracing.com/parts/HOK-2460HKR/
As I can see on E-bay, I can buy LS1 engine with auto trans for about 2500-3000$, which is about 4000-5000$ with all expenses to bring it to my country (I have friends who are familiar with importing USA cars via containers). So, for this amount of money, I think that is better choice for me. Correct me if I'm wrong
my car/engine has 52000 miles and I think that it's ready to build up
I don't like nitro, this is street car so I want that power all the time. I don't defined budget for this, but there is no need to buy everything at once.
I spent about 6000$ in last two years to repair the car, because it was in very bad shape, and this is only GTA 5.7 in my country (Serbia). Money is not the problem, but I want to see here is it better to build up L98, or just to buy LS1 with tranny and get 350HP immediately
If I need to spend 3000-4000$ to build up L98, I'd rather buy LS1.
What could I espect from these parts:
First: http://www.firstfuelinjection.com/PDRM1966.JPG
Headers: http://www.summitracing.com/parts/HOK-2460HKR/
As I can see on E-bay, I can buy LS1 engine with auto trans for about 2500-3000$, which is about 4000-5000$ with all expenses to bring it to my country (I have friends who are familiar with importing USA cars via containers). So, for this amount of money, I think that is better choice for me. Correct me if I'm wrong
Last edited by shone190; 07-20-2011 at 05:42 AM.
Trending Topics
#8
Supreme Member
iTrader: (20)
Re: +100HP from L98
LS1 with headers/exhaust and a tune will do 330-350whp depending on trans and year motor Thats pretty stout.
BUT for 3000 bucks you likely can get that power and exceed it with the L98 provided the bottom end is still in good condition.
If you did heads/cam/intake on the stock bottom end shortblock, you can turn near 6400 rpm and make 350-375whp or more depending on the setup.
I'd go stealth ram if you can, as its cheaper than the FIRST TPI and easier to work with. But the FIRST will do great if you want to go TPI.
Get some heads, like Pro-Filer 195s, AFR 195's, Dart pro 1 200's, brodix race rites 200's or similar range of heads. Put in a 268XFI cam for a good mix of streetability, ease of tune and 350whp power potential. Or stretch it with a 280XFI cam and shoot for closer to 375whp+.
My buddy's car did old AFR190 heads with stealthram and 280xfi comp cam and even tho his valvesprings were bad, it still ran 12.2's in warm air at 112 mph. It only made 330whp before suffering bad valve float. With proper spring control it would have been a solid 350's whp car and went 11.9's or quicker. Probably 114mph+. New style heads would have been a 375whp car easily and mid 11's at 116
BUT for 3000 bucks you likely can get that power and exceed it with the L98 provided the bottom end is still in good condition.
If you did heads/cam/intake on the stock bottom end shortblock, you can turn near 6400 rpm and make 350-375whp or more depending on the setup.
I'd go stealth ram if you can, as its cheaper than the FIRST TPI and easier to work with. But the FIRST will do great if you want to go TPI.
Get some heads, like Pro-Filer 195s, AFR 195's, Dart pro 1 200's, brodix race rites 200's or similar range of heads. Put in a 268XFI cam for a good mix of streetability, ease of tune and 350whp power potential. Or stretch it with a 280XFI cam and shoot for closer to 375whp+.
My buddy's car did old AFR190 heads with stealthram and 280xfi comp cam and even tho his valvesprings were bad, it still ran 12.2's in warm air at 112 mph. It only made 330whp before suffering bad valve float. With proper spring control it would have been a solid 350's whp car and went 11.9's or quicker. Probably 114mph+. New style heads would have been a 375whp car easily and mid 11's at 116
#9
Member
iTrader: (2)
Join Date: Oct 2010
Location: San Antonio, Tx
Posts: 230
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1988 IROC-Z
Engine: 5.7 TPI with zz4 heads
Transmission: 700R4
Axle/Gears: 9 bolt BW
Re: +100HP from L98
Quick question Is this a daily driver or weekend car? If it's your daily driver and will be so for a couple of year's Id do an LS1 due to a good balance of power (325hp) and MPG (20 city-27hwy)
If its just a weekend car and have absolutely no plan's on DD just upgrade what you have, Its gonna be cheaper and less of a pain in the *** to get the power you want. Intake, cam, exhaust are a must with decent head's and cam alone you can easily add up to 70hp exhaust 15hp tune 15hp and there it is.
If its just a weekend car and have absolutely no plan's on DD just upgrade what you have, Its gonna be cheaper and less of a pain in the *** to get the power you want. Intake, cam, exhaust are a must with decent head's and cam alone you can easily add up to 70hp exhaust 15hp tune 15hp and there it is.
#10
Member
Thread Starter
Re: +100HP from L98
Great info
So you think that FIRST TPI with heads and cam is the way to get 300-350HP.
When You said AFR 195 heads, od Dart, do You think about something like this?
http://www.summitracing.com/parts/DRT-13200010/
http://www.summitracing.com/parts/AFR-1040NP/
Which 280xfi cam do you suggest (Price range is between 140$ and 1100$ )?
http://www.summitracing.com/search/?...Ns=Price%7cAsc
I didn't see that Stealth ram is cheaper than FIRST TPI, but never mind.
If I need all these parts for Stealth setup, this is almost the same price as FIRST:
http://www.summitracing.com/parts/HLY-112-503/
http://www.summitracing.com/parts/WND-7540/
http://www.summitracing.com/parts/HLY-534-186/
So you think that FIRST TPI with heads and cam is the way to get 300-350HP.
When You said AFR 195 heads, od Dart, do You think about something like this?
http://www.summitracing.com/parts/DRT-13200010/
http://www.summitracing.com/parts/AFR-1040NP/
Which 280xfi cam do you suggest (Price range is between 140$ and 1100$ )?
http://www.summitracing.com/search/?...Ns=Price%7cAsc
I didn't see that Stealth ram is cheaper than FIRST TPI, but never mind.
If I need all these parts for Stealth setup, this is almost the same price as FIRST:
http://www.summitracing.com/parts/HLY-112-503/
http://www.summitracing.com/parts/WND-7540/
http://www.summitracing.com/parts/HLY-534-186/
#12
Junior Member
iTrader: (1)
Join Date: Oct 2008
Location: Los Angeles, CA
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro IROC-Z28
Engine: Stock L98
Transmission: 700R-4
Axle/Gears: 3.23
Re: +100HP from L98
Have you seen this?
https://www.thirdgen.org/forums/tpi/...injection.html
You may want to check it out since you're considering the first system.
You should also try to contact Dyno Don or 1989GTATransAm if you plan on keeping TPI, they are board experts
https://www.thirdgen.org/forums/tpi/...injection.html
You may want to check it out since you're considering the first system.
You should also try to contact Dyno Don or 1989GTATransAm if you plan on keeping TPI, they are board experts
#14
Member
Join Date: Oct 2010
Location: colorado
Posts: 271
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1987 formula
Engine: 305 tpi
Transmission: t5
Axle/Gears: 3.45
Re: +100HP from L98
even for cheap you can go with new intake piping with cold air intake piping, atleast 1.6 roller rockers, adjustable fuel pressure regulator, exhaust. but there is always the easiest way of just turbo or supercharging it.
#15
Supreme Member
iTrader: (20)
Re: +100HP from L98
box stock FIRST system is a great TPI system and will support all that you need for 320-350whp.
I wouldnt run the 280xfi on that setup unless you wanted to push the limits of the intake, or went with a stealth ram setup. Its really not necessary, that cam can do almost 400whp in the right setup.
the 268xfi is a good 350whp cam, its very mild but with good heads its a powerhouse. I'd run that. it will sound very mild and get great mileage, be easy to tune and yet make power when combined with a good head like Profiler 195's or AFR 195's or one of the better DART/BRodix 200 packages.
What you want is the cam for OEM hydraulic roller motors 87-99 since yours is a 88. usually 250-320 bucks. Dont even need to use XFI series, but they work well. The XE grinds from comp are decent too with 1.6 rockers. IF you dont want comp, Lunati would be a nice choice..they have a nice 268 cam thats abit more aggressive than comps...their voodoo lineup. It will make good power.
Its up to you. Technically you dont even need heads that big to make 320+whp. I've seen mild cleaned up L98 castings make 320whp with a hotcam. Its just nice to have good heads and mild cam to make the big power. Makes more area under the curve and is smoother running. Just my opinion
I wouldnt run the 280xfi on that setup unless you wanted to push the limits of the intake, or went with a stealth ram setup. Its really not necessary, that cam can do almost 400whp in the right setup.
the 268xfi is a good 350whp cam, its very mild but with good heads its a powerhouse. I'd run that. it will sound very mild and get great mileage, be easy to tune and yet make power when combined with a good head like Profiler 195's or AFR 195's or one of the better DART/BRodix 200 packages.
What you want is the cam for OEM hydraulic roller motors 87-99 since yours is a 88. usually 250-320 bucks. Dont even need to use XFI series, but they work well. The XE grinds from comp are decent too with 1.6 rockers. IF you dont want comp, Lunati would be a nice choice..they have a nice 268 cam thats abit more aggressive than comps...their voodoo lineup. It will make good power.
Its up to you. Technically you dont even need heads that big to make 320+whp. I've seen mild cleaned up L98 castings make 320whp with a hotcam. Its just nice to have good heads and mild cam to make the big power. Makes more area under the curve and is smoother running. Just my opinion
#16
Member
Thread Starter
Re: +100HP from L98
OK, so what exactly do You suggest?
What could I expect from FIRST TPI and Hooker headers 2460?
http://www.summitracing.com/parts/HOK-2460HKR/
Shipping to my country is expensive, so I want to know what could I do with stock heads
Is there any purpose to swap just cam (without heads), after FIRST TPI and headers swap?
What could I expect from FIRST TPI and Hooker headers 2460?
http://www.summitracing.com/parts/HOK-2460HKR/
Shipping to my country is expensive, so I want to know what could I do with stock heads
Is there any purpose to swap just cam (without heads), after FIRST TPI and headers swap?
#17
Supreme Member
iTrader: (20)
Re: +100HP from L98
Do you have a machine shop that can take your stock heads, and cut the spring pockets out abit, and install screw in studs, and do a new valve job?
If so, you can cam it up and make decent power on stock castings but getting to 350whp likely wont happen. With abit of port work and a big cam, it MAY do it like the LT1 guys. Their heads flow a good 20 cfm more stock so the Iron L98s need opened up to compete with that.
If so, you can cam it up and make decent power on stock castings but getting to 350whp likely wont happen. With abit of port work and a big cam, it MAY do it like the LT1 guys. Their heads flow a good 20 cfm more stock so the Iron L98s need opened up to compete with that.
#18
Supreme Member
iTrader: (9)
Join Date: Mar 2007
Location: Raleigh, NC
Posts: 1,804
Likes: 0
Received 2 Likes
on
2 Posts
Car: 1988 Flame Red Trans am GTA
Engine: Forged 355 4 Bolt, FIRST TPI
Transmission: 700r4
Axle/Gears: ls1 torsen 3.42 gear
Re: +100HP from L98
a box stock first is good up to 450hp NA according to a few people... waaay more than any stockish or midly ported tpi can do.. id say for a stockish look and still retain the tpi look....do this for a budget build
vortec heads (make sure you get them to handle to about .550 lift)
FIRST tpi (you can get the vortec style FIRST manifold that fits vortec heads)
gm hotcam ( very cheap but good streetable cam)
headers
full exhuast
tune
do all of that and you should easily be over 320whp...... im aiming to get at least 1 hp per cubic inch at the rear wheels.... since i have a 355sbc i want at least 355whp and 355wtq.....
vortec heads (make sure you get them to handle to about .550 lift)
FIRST tpi (you can get the vortec style FIRST manifold that fits vortec heads)
gm hotcam ( very cheap but good streetable cam)
headers
full exhuast
tune
do all of that and you should easily be over 320whp...... im aiming to get at least 1 hp per cubic inch at the rear wheels.... since i have a 355sbc i want at least 355whp and 355wtq.....
#19
Member
Join Date: Sep 2009
Location: Scottsdale, AZ
Posts: 186
Received 0 Likes
on
0 Posts
Car: 1991 RS L99 1992 Z28 L98 Heritage
Engine: L99 L98
Transmission: 6L80E / 700R4
Axle/Gears: 3.23 LSD disc (both)
Re: +100HP from L98
LS1 with headers/exhaust and a tune will do 330-350whp depending on trans and year motor Thats pretty stout.
BUT for 3000 bucks you likely can get that power and exceed it with the L98 provided the bottom end is still in good condition.
If you did heads/cam/intake on the stock bottom end shortblock, you can turn near 6400 rpm and make 350-375whp or more depending on the setup.
I'd go stealth ram if you can, as its cheaper than the FIRST TPI and easier to work with. But the FIRST will do great if you want to go TPI.
Get some heads, like Pro-Filer 195s, AFR 195's, Dart pro 1 200's, brodix race rites 200's or similar range of heads. Put in a 268XFI cam for a good mix of streetability, ease of tune and 350whp power potential. Or stretch it with a 280XFI cam and shoot for closer to 375whp+.
My buddy's car did old AFR190 heads with stealthram and 280xfi comp cam and even tho his valvesprings were bad, it still ran 12.2's in warm air at 112 mph. It only made 330whp before suffering bad valve float. With proper spring control it would have been a solid 350's whp car and went 11.9's or quicker. Probably 114mph+. New style heads would have been a 375whp car easily and mid 11's at 116
BUT for 3000 bucks you likely can get that power and exceed it with the L98 provided the bottom end is still in good condition.
If you did heads/cam/intake on the stock bottom end shortblock, you can turn near 6400 rpm and make 350-375whp or more depending on the setup.
I'd go stealth ram if you can, as its cheaper than the FIRST TPI and easier to work with. But the FIRST will do great if you want to go TPI.
Get some heads, like Pro-Filer 195s, AFR 195's, Dart pro 1 200's, brodix race rites 200's or similar range of heads. Put in a 268XFI cam for a good mix of streetability, ease of tune and 350whp power potential. Or stretch it with a 280XFI cam and shoot for closer to 375whp+.
My buddy's car did old AFR190 heads with stealthram and 280xfi comp cam and even tho his valvesprings were bad, it still ran 12.2's in warm air at 112 mph. It only made 330whp before suffering bad valve float. With proper spring control it would have been a solid 350's whp car and went 11.9's or quicker. Probably 114mph+. New style heads would have been a 375whp car easily and mid 11's at 116
#20
Supreme Member
iTrader: (20)
Re: +100HP from L98
Yes as long as car isnt super heavy and most arent. Also proper air conditions apply. You wont get there in colorado 5800' up but say maryland in november with 50 deg air it will run hard.
My iroc with power everything and leather was 3450 lbs with me in it back in late 2000's. Now i am 30 lbs heavier lol but for most part, 3400 lb or so is easy to get to especially if you run separate rims for drag race and skinnies up front. That drops 70lbs by itself
Combination of parts has to work together and car needs to make use out of the power thru chassis tuning
My iroc with power everything and leather was 3450 lbs with me in it back in late 2000's. Now i am 30 lbs heavier lol but for most part, 3400 lb or so is easy to get to especially if you run separate rims for drag race and skinnies up front. That drops 70lbs by itself
Combination of parts has to work together and car needs to make use out of the power thru chassis tuning
Thread
Thread Starter
Forum
Replies
Last Post